KESSLER

Monitoring orbital debris to safeguard our access to space

KESSLER is a CubeSat-class nanosatellite developed by ASTREO to detect and map space debris in low Earth orbit (LEO).

Using a miniaturized active radar system, KESSLER will collect real-time data on debris density and distribution, paving the way for smarter, more sustainable access to space.

Why it matters

Over 130 million objects larger than 1 mm currently orbit Earth — and only a tiny fraction of them are active spacecraft. Most are fragments of rockets, satellites, and past collisions, each one a potential threat.

In low Earth orbit (LEO), even a piece just a few millimeters wide can cause catastrophic damage due to the high relative velocities. As shown in the image, our planet is surrounded by a dense cloud of debris, with:

10,200 active objects (cyan)
50,000+ objects >10 cm (red)
1.2 million objects >1 cm (orange)
130 million objects >1 mm (yellow)

This escalating risk is known as the Kessler Syndrome — a chain reaction where debris causes further collisions, creating even more fragments. If left unmanaged, this could make entire orbital regions unusable.

KESSLER was designed to face this challenge head-on, by providing real, high-resolution data on the evolving space debris environment.

Technology

KESSLER is equipped with an advanced Active Electronically Scanned Array (AESA) radar, designed to detect small debris objects in LEO with high precision. The system operates in the 20 GHz K-band, offering centimeter-level resolution and real-time tracking capabilities.

Key features include:

Electronically steerable beam, enabling fast and flexible scanning without mechanical movement
Modular patch design, allowing the radar to adapt to mission needs and optimize efficiency in space
Pulse compression, improving spatial and temporal resolution for accurate detection at varying distances

This radar system is compact, scalable, and specifically optimized for detecting space debris, making KESSLER a pioneering platform for in-orbit situational awareness.